I thought I might share with you what Ive been doing.
I hope this may not be the wrong place to post this thread.
I have a 1986 Nissan Bluebird wagon 2000 cc (no EFI on this one),
which I have modified the intake track to be different than what is
out there, I ignored what I read on the internet about porting once
again and did my own thing.
I have improve fuel efficiency under highway driving conditions, I
have experienced as high as 60 mpg (4.71 L/100km) over a 220
km journey on a hot summer's day cruising around 80 km/h.
I can also get 15 mpg as well.
When I first ran my second engine with a STD timing a little
retarded I experienced very poor fuel efficiency under high load
and rpm but I had plenty of power, I also was able to exceed the
delivery from a single fuel pump (electric 1 L/min).
My engine timing is linear with rpm and depending on what
temperature the engine is run at I need to fire it in the power stroke
eg after TDC to stop knocking
I use a wire wheel to port my manifold and ports, I welded an
extension shaft to it ro reach in.
My ports look like this
have a look at my web site too there are intake recordings.
Visit My Website
on the sound page.
I have a stock carby and my vac sec are fully open at 2000 rpm
it used to be approx 4000 so I can only guess at the air flow.
I have a video of fuel flowing from vac sec with no load this should not happen normally.